Veterinary World 2011, Vol.4 (1):12-14
RESEARCH
Prevalence and Pathology of Trichomoniasis in Free – Living
Urban Pigeons in the City of Mosul, Iraq
Hafidh I. Al- Sadi* and Aws Z. Hamodi
Department of Pathology and Poultry Diseases,
College of Veterinary Medicine, University of Mosul, Iraq
Corresponding author email: hafidhalsadi@yahoo.com, Tel. 009647703099365
Abstract
The present study was undertaken to determine the prevalence of trichomoniasis and its pathology in pigeons. A
total of 100 free living urban pigeons were collected during the months August and September 2007. The overall
prevalence was 16%. In infected pigeons, yellowish – white masses of caseous necrotic material were seen
grossly in the oral cavity, esophagus, crop, and proventiculus. Pale to yellow necrotic areas were noted in the
liver. Multiple foci of caseous necrosis were seen microscopically in the oral mucosa together with heavy
infiltration of inflammatory cells (mainly heterophils). Foci of necrotic inflammation were seen in the liver and
there was thickening of the lining mucosa of the esophagus due to extensive infiltration of heterophils.
Collections of necrotic material were seen in the mucosa and submucosa of the esophagus. Infection occurred
more frequently in young than in adult pigeons. A higher prevalence of the infection was noted in male than in
female pigeons. In all of the infected pigeons, trichomoniasis occured in the absence of apparent secondary
disease. It was concluded that trichomonad infection is fairly common in free living urban pigeons in the city of
Mosul, Iraq.
Key words: Free living pigeons, prevalence, pathology, trichomoniasis, Mosul, Iraq.
Introduction
Trichomoniasis is an infection with the
flagellated protozoan Trichomonas gallinae and is
commonly found in pigeons, turkeys, chickens,
hawks, mourning doves, golden eagles, falcons, and
bustards (Levine, 1995). Infected birds show signs of
dullness, depression, and diarrhea, characterized by
yellow pasty stools. The disease is responsible for
economic losses since it is associated with high
mortality along with very high morbidity (Samour et
al., 1995). Among young pigeons, T. gallinae
infection may result in a high mortality within 10 days
and a high incidence of latent infection (up to 90%) has
also been reported (Soulsby, 1982). The purposes of
the present study were to describe the prevalence and
pathological lesions of trichomoniasis in free – living
urban pigeons in the city of Mosul, Iraq and to study
the influence of factors such as age (immature vs.
adult), sex, weight and health status of the pigeons on
prevalence of the disease.
Material and Methods
A total of 100 free living urban pigeons
(Columba livia) bought from the local markets of
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Mosul city, Iraq during the months August and
September, 2007, were included in this study. The
body weight, health status, sex, and age of each bird
were recorded. Gross examination of oral cavity was
done and swab was taken from the throat or from the
oral cavity. The swabs were processed through direct
smear method and then subsequently with Wright –
Giemsa, staining techniques (Coles, 1980) to identify
the T. gallinae. Complete postmortem examination of
each bird was performed and tissue specimens were
collected from the oral cavity, esophagus, crop,
intestines, liver, and the lungs. They were fixed in 10%
neutral formalin solution for 48 to 72 hours and then
washed under tap water, dehydrated in ascending
grades of alcohol, cleared in xylol and embedded in
paraffin wax (60 – 62 C melting point). Sections of 4 –
6 µm thickness were cut and stained with hematoxylin
and eosin (Kiernan, 1999).
Results
The overall prevalence rate of avian trichomoniasis was 16%. Grossly, yellowish – white masses of
caseous necrotic material were seen in the oral cavity,
esophagus, crop, and proventiculus (Figs. 1 and 2).
Pale to yellow necrotic areas were noted in the liver.
Veterinary World, Vol.4 No.1 January 2011
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Prevalence and Pathology of Trichomoniasis in Free – Living Urban Pigeons in the City of Mosul, Iraq.
Microscopically, multiple foci of caseous necrosis
were seen in the oral, esophageal and crop mucosae
together with heavy infiltration of inflammatory cells
(mainly heterophils) (Figs. 3 and 4). In some cases the
necrotic area assumed concentric rings. Examination
of the liver revealed multiple foci of necrotic
inflammation and there was thickening of the lining
mucosa of the esophagus due to extensive infiltration
of heterophils. Collections of necrotic material were
seen in the mucosa and submucosa of the esophagus.
Multiple foci of necrosis together with infiltrations of
inflammatory cells (heterophils and lymphocytes)
were seen in the liver tissue. In the intestines, necrosis
of the tips of some of the villi and the accumulation of
the necrotic material in the intestinal lumen were seen.
Trichomoniasis occurred more frequently in
young than in adult pigeons. A higher prevalence of
the infection was seen in male than in female pigeons.
The range of weight of affected pigeons was 300 – 400
gm and no secondary disease was found.
Discussion
In the present study, the prevalence of
trichomoniasis in pigeons in the city of Mosul, Iraq
was 16%. In comparison, prevalence of trichomoniasis was 40.6% in squab pigeons of Egypt (Abdel –
Motelib et al., 1997). Toro et al., (1999) recorded the
prevalence of trichomoniasis in free living pigeons in
the city of Santiago as 11%. The overall prevalence
rate of trichomoniasis in domestic and wild pigeons
maintained at the Zoological Garden, Lahore and
Tollinton Market, Lahore, Pakistan was found to be
43% (Saleem et al., 2008). A higher incidence of
trichomoniasis (59%) was reported in racing pigeons
in Australia (McKeon et al., 1997). The incidence of
trichomoniasis was 38.8% in budgerigars, Senegal
doves, and racing pigeons. Villanua et al. (2006) found
the prevalence of trichomoniasis in common wood
pigeon in Spain as 34.2%. Gulegen et al. (2005)
reported 75.78% prevalence rate in domestic pigeon.
In a study monitoring the presence and annual
variation of T. gallinae for 6 years in a local mourning
dove population using hunter – killed doves, a 5.6% of
the tested samples were positive for the presence of T.
gallinae (Schulz et al., 2005). Anderson et al. (2009)
recorded a prevalence rate of trichomoniasis of 1.7%
in house finches, 0-6.3% in corvids and 0.9% in
mockingbirds. Krone et al. (2005) reported that the
prevalence of trichomoniasis in northern goshawks
from the Berlin area of northeastern Germany was
69.7% in 1998, 73.0% in 1999, 55.8% in 2000 and
62.9% in 2001. The variation of the prevalence rate in
the various studies is expectable in view of the many
factors that affect occurrence of the disease such as the
climatic conditions, geographical difference, seasonal
variation, resistance of the host, different feeding
habits, age of birds, difference in housing conditions,
and others. A similar explanation has been made by
others (Saleem et al., 2008).
In this study, trichomoniasis occurred more
frequently in male than in female pigeons. This result
is in discrepancy with that of Villanua et al. (2006)
who found no significant difference in prevalence
between males and females. This discrepancy could be
B
B
----->
A
B
A
B
-
---->
Figure. 1. Yellow necrotic
masses of variable size in the
oral mucosa of a pigeon with
trichomoniasis.
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Figure. 2 Whitish necrotic
masses in the mucosa of the
esophagus and the crop of a
pigeon with trichomoniasis
Figure.3.Photomicrograph
of the oral cavity of a pigeon
with trichomoniasis. The
accumulation of necrotic
material (A) and the
infiltration of inflammatory
cells (B) in the submucosa
could be seen. H&E. X90.
Veterinary World, Vol.4 No.1 January 2011
Figure.4.Photomicrograph
of the wall of the crop of a
Pigeon with trichomoniasis.
Necrotic material could be
seen on the mucosa (A) and
submucosa (B). Infiltration
of inflammatory cells could
be also seen in the
submucosa (arrow). H&E.
X90.
13
Prevalence and Pathology of Trichomoniasis in Free – Living Urban Pigeons in the City of Mosul, Iraq.
due to the difference in the types of pigeons used in the
two studies. The finding of trichomoniasis more
commonly in young than in adult pigeons is in
accordance with that of others (Butcher, 2003;
McDougald, 2003). Carrier pigeons are known to
transmit Trichomonads to their young during feeding
(Butcher, 2003). In the present study, trichomoniasis
was reported in apparently healthy pigeons. This
finding may indicate that trichomoniasis could occur
in the absence of secondary disease.
The pathological lesions described in the present
study were basically inflammatory, ulcerative, and
necrotic in nature. They were more predominant in the
oral cavity, esophagus, crop and proventriculus.
Similar lesions have been described for naturally –
occurring and experimentally induced trichomoniasis
in pigeons (Kennedy, 2001; McDougald, 2003).
3.
4.
5.
6.
7.
8.
Conclusion
Result of the present study indicated that
trichomonad infection is fairly common in free living
urban pigeons in Mosul city, Iraq. Severe necrotic
lesions were seen in the oral cavity, esophagus, crop
and proventiculus of infected pigeons. A higher
occurrence of the disease was found in young than in
adult and in male than in female pigeons. The presence
of a secondary disease was not a prerequisite for the
occurrence of trichomonad infection.
Acknowledgement
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2.
10.
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The authors are thankful to the College of
Veterinary Medicine, University of Mosul, Iraq for
providing facilities to conduct the present research
work.
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